Compost is the dark, crumbly, earthy-smelling material produced by the managed decomposition of organic materials such as yard trimmings and food scraps. Compost is valued for its ability to enhance soil structure and quality. It adds organic matter to soil, improves plant growth and water retention, cuts chemical fertilizer use, and stems stormwater run-off and soil erosion.

Compost also protects the climate: it sequesters carbon in soil and it reduces methane emissions from landfills by cutting the amount of biodegradable materials disposed. (Methane is a greenhouse gas with a global warming potential 72 times more potent than CO2 in the short-term.) A growing body of evidence demonstrates the effectiveness of compost to store carbon in soil for a wide range of soil types and land uses.

State of Composting in the U.S. is the first comprehensive review of composting basics, national and state statistics, job generation data, model programs, and policy opportunities. ILSR’s companion report, Growing Local Fertility: A Guide to Community Composting, features successful community-scale composting initiatives, their benefits, tips for replication, key start-up steps, and the need for private and public sector support.